NOVEL GLASS-FORMING ORGANIC MATERIALS .1. ADAMANTANE WITH PENDANT CHOLESTERYL, DISPERSE RED-1, AND NEMATOGENIC GROUPS

Adamantane was employed as an excluded-volume core for the synthesis o f two- and four-arm liquid crystalline, as well as amorphous, molecula r systems capable of vitrification upon thermal quenching. It was foun d that (-)-cholesterol as the side arm exhibited a smectic A and a cho lesteric mesophase, whereas 1-phenyl-2-(6-cyanonaphth-2-yl)ethyne and cyanotolan showed a nematic mesophase in both two- and four-arm system s. Furthermore, disperse red 1 resulted in amorphous, nonmesogenic mat erials. In general, the four-arm systems tend to elevate T-g and T-c a nd to depress recrystallization of the quenched glass upon heating in comparison to the two-arm systems. It was also found that with 1-pheny l-2-(6-cyanonaphth-2-yl)ethyne, the four-arm adamantane showed an elev ated T-g but a somewhat depressed T-c relative to the three-arm cycloh exane counterpart.